Method and apparatus related to servicing of liquid ring pumps

ABSTRACT

A method for decoupling a liquid ring pump component from a liquid ring pump for facilitating maintenance services, the liquid ring pump comprising a housing defining an annular chamber and a shaft passing into the chamber, the component being disposed around the shaft and coupled between the shaft and the housing, the method comprising: coupling, using a first fixing member, a first end of the shaft to the housing thereby to prevent or oppose movement of the shaft relative to the housing in at least a radial direction; and, thereafter, sliding the component along the shaft in a direction along the shaft from the housing towards the first end of the shaft, thereby spacing apart the housing and the component.

This application is a national stage entry under 35 U.S.C. § 371 ofInternational Application No. PCT/IB2019/052065, filed Mar. 14, 2019,which claims the benefit of GB Application 1804110.3, filed Mar. 14,2018. The entire contents of International Application No.PCT/IB2019/052065 and GB Application 1804110.3 are incorporated hereinby reference.

TECHNICAL FIELD

The present disclosure relates to methods and apparatus for decouplingliquid ring pump components from liquid ring pumps, for example toenable or facilitate maintenance services to be performed on the liquidring pump and components thereof.

BACKGROUND

Liquid ring pumps are a known type of pump. Liquid ring pumps typicallyinclude a housing that defines a chamber, a shaft passing into thechamber, an impeller mounted to the shaft, and a drive system such as amotor operably connected to the shaft to drive the shaft. The impellerand shaft are positioned eccentrically within the chamber.

In operation, the chamber is partially filled with an operating liquid.When the drive system drives the shaft and the impeller, a liquid ringis formed on the inner wall of the chamber thus providing a seal thatisolates individual volumes between adjacent impeller vanes. Theimpeller and shaft are eccentric to the liquid ring. This results in acyclic variation of the volumes enclosed between adjacent vanes of theimpeller and the liquid ring.

In a portion of the chamber where the liquid ring is further away fromthe shaft, there is a larger volume between adjacent impeller vaneswhich results in a smaller pressure therein. This allows the portionwhere the liquid ring is further away from the shaft to act as a gasintake zone. In a portion of the chamber where the liquid ring is closerto the shaft, there is a smaller volume between adjacent impeller vaneswhich results in a larger pressure therein. This allows the portionwhere the liquid ring is closer to the impeller to act a gas dischargezone.

Examples of liquid ring pumps include single-stage liquid ring pumps andmulti-stage liquid ring pumps. Single-stage liquid ring pumps involvethe use of only a single chamber and impeller. Multi-stage liquid ringpumps (e.g. two-stage) involve the use of multiple chambers connected inseries.

Preferably, liquid ring pumps undergo maintenance procedures. Forexample, pump bearings may be periodically lubricated. Also, liquid ringpumps may be regularly cleaned to remove solid matter (such as dirt,sand, or lime deposits) that has entered and collected in the liquidring pump through the operating liquid and/or the pumped gases.

Also, liquid ring pumps may undergo repair procedures to repair orreplace damaged or failed components. Components of the liquid ringpump, including but not limited to bearings, belt drives, and seals, maybecome damaged or fail, for example, as a result of cavitation, erosion,and/or corrosion.

SUMMARY

Typically, a liquid ring pump is installed such that, in operation, theshaft of the liquid ring pump is substantially horizontal (e.g.substantially parallel with a surface upon which the liquid ring pump islocated or installed). Maintenance and/or repair procedures for a liquidring pump tend to involve disassembly or loosening of at least part ofthe liquid ring pump. However, conventionally, such disassembly of theliquid ring pump while the shaft is oriented horizontally tends to riskunwanted bending of the shaft. Such bending of the shaft may damage theshaft and may also cause the impeller vanes to collide with the walls ofthe housing, which may damage the vanes and/or housing.

Conventionally, to alleviate this problem, maintenance and/or repairprocedures typically include suspending the liquid ring pump above theground, and rotating it through about 90° so that its shaft issubstantially vertical. Maintenance and/or repair of the liquid ringpump, including partial disassembly, are then performed.

However, apparatus for lifting, rotating, and suspending a liquid ringpump is large and costly. Furthermore, there tends to be an increasedlikelihood that component parts disassembled or loosened duringmaintenance may fall from the suspended liquid ring pump and becomedamaged.

The present inventors have realised that it would be beneficial toprovide a maintenance or repair procedure for a liquid ring pump thatmay be implemented while the shaft of the liquid ring pump is orientedhorizontally, and which also reduces or eliminates unwanted shaftbending. The present inventors have further realised that it would bebeneficial to provide a way of at least partially disassembling a liquidring pump while the shaft of the pump is oriented horizontally in a waythat reduces or eliminates unwanted shaft bending.

The present inventors have realised that it would be beneficial toprovide a maintenance or repair procedure for a liquid ring pump thatavoids lifting, rotating, and suspending above the ground the liquidring pump.

In a first aspect, the present disclosure provides a method fordecoupling a liquid ring pump component from a liquid ring pump Theliquid ring pump comprises a housing defining an annular chamber and ashaft passing into the chamber. The liquid ring pump component isdisposed around the shaft and coupled between the shaft and the housing.The method comprises: coupling, using a first fixing member, a first endof the shaft to the housing thereby to prevent or oppose movement of theshaft relative to the housing in at least a radial direction; and,thereafter, sliding the component along the shaft in a direction alongthe shaft from the housing towards the first end of the shaft, therebyspacing apart the housing and the component.

The liquid ring pump component may be configured to, when the liquidring pump component is disposed around the shaft and coupled between theshaft and the housing, prevent or oppose movement of the shaft relativeto the housing in a radial direction and/or axial direction.

An impeller comprising a plurality of impeller blades or vanes may bemounted to the shaft and located within the chamber such that rotationof the shaft causes the impeller to rotate within the chamber.

The method may further comprise, while the component and the housing arespaced apart, inspecting, cleaning, repairing or replacing the componentor a further component of the liquid ring pump. The method may furthercomprise sliding the component along the shaft in a direction along theshaft from the first end of the shaft towards the housing, and couplingthe component between the shaft and the housing.

The first fixing member may be a member selected from the group ofmembers consisting of: a fixing bracket configured to fixedly attachbetween the first end of the shaft and the housing, and a support memberconfigured to be coupled between the shaft and a surface upon which theliquid ring pump is located.

The first fixing member may be a bracket comprising a base member, twoside members extending substantially perpendicularly from opposite endsof the base member, and two arms, each arm being attached to arespective side member at the opposite end of that side member to thebase member, the arms extending outwards from the side memberssubstantially parallel to the base member. Coupling the first end of theshaft to the housing may comprise bolting the fixing bracket to theshaft and the housing. Bolting the fixing bracket to the shaft and thehousing may comprise inserting a bolt into a hole in the housing, thehole being a hole via which a bearing assembly or bearing assembly coveris bolted to the liquid ring pump.

The method may further comprise coupling, using a second fixing member,the shaft to the housing. The second fixing member may be configured toprevent or oppose movement of the shaft relative to the housing in atleast a radial direction. The second fixing member may be coupled to theshaft at a position along the length of the shaft that is further awayfrom the first end than the component. The method may further comprisedecoupling the first fixing member from the first end of the shaft, andremoving the component from the shaft at the first end of the shaft. Themethod may further comprise: inspecting, cleaning, repairing orreplacing the removed component, thereby to provide a reconditioned orreplacement component; disposing the reconditioned or replacementcomponent around the shaft at the first end of the shaft; coupling,using a fixing member, a first end of the shaft to the housing, thefixing member configured to prevent or oppose movement of the shaftrelative to the housing in at least a radial direction; decoupling thesecond fixing member from the shaft; sliding the reconditioned orreplacement component along the shaft in a direction along the shaftfrom the first end of the shaft towards the housing; coupling thereconditioned or replacement component between the shaft and thehousing; and, thereafter, decoupling the fixing member from the firstend of the shaft.

The second fixing member may be a member selected from the group ofmembers consisting of: a fixing bracket configured to fixedly attachbetween the shaft and the housing, and a support member configured to becoupled between the shaft and a surface upon which the liquid ring pumpis located.

The component may be a mechanical seal.

The method may further comprise: prior to coupling the first end of theshaft to the housing using the first fixing member, removing, from theliquid ring pump at or proximate to the first end of the shaft, one ormore liquid ring pump components selected from the group of componentsconsisting of: a bearing cover, a bolt, a spacer, a washer, a bearingassembly, a bearing, a seal, a lantern ring, a V-ring, and a circlip.The method may further comprise inspecting, cleaning, repairing orreplacing the removed one or more liquid ring pump components, therebyto provide a reconditioned or replacement one or more liquid ring pumpcomponents.

Coupling, using the first fixing member, the first end of the shaft tothe housing may further prevent or oppose axial and/or rotationalmovement of the shaft relative to the housing.

The shaft may be retained in a substantially horizonal orientationduring the method. The term “horizontal” may refer to being parallel tothe plane of the horizon, or parallel to the plane of a surface uponwhich the liquid ring pump is located or installed.

The method may further comprise: coupling, using a third fixing member,a second end of the shaft to the housing thereby to prevent or opposemovement of the shaft relative to the housing in at least a radialdirection, the second end of the shaft being opposite to the first end;and, thereafter, sliding a further component along the shaft in adirection along the shaft from the housing towards the second end of theshaft, thereby spacing apart the housing and the component. The steps ofcoupling the second end of the shaft to the housing and sliding thefurther component along the shaft towards the second end of the shaftmay overlap temporally at least to some extent with the steps ofcoupling the first end of the shaft to the housing and sliding thecomponent along the shaft towards the first end of the shaft.

In a further aspect, the present disclosure provides a systemcomprising: a liquid ring pump comprising a housing defining an annularchamber, a shaft coupled to the housing and passing through the housinginto the chamber, and a component disposed around the shaft and coupledbetween the shaft and the housing and configured to prevent or opposemovement of the shaft relative to the housing in at least a radialdirection; and a fixing member configured to couple together a first endof the shaft and the housing thereby to prevent or oppose movement ofthe shaft relative to the housing in at least the radial direction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration (not to scale) of a liquid ring pump.

FIG. 2 is a process flow chart showing certain steps of a maintenanceand/or repair procedure for the liquid ring pump.

FIG. 3 is a schematic illustration (not to scale) showing a bearingcover being removed from the liquid ring pump.

FIG. 4 is a schematic illustration (not to scale) showing a bearingassembly being removed from the liquid ring pump.

FIG. 5 is a schematic illustration (not to scale) showing an explodedview of the bearing assembly.

FIG. 6 is a schematic illustration (not to scale) illustrating a fixingbracket being attached to the liquid ring pump.

FIG. 7 is a schematic illustration (not to scale) illustrating thefixing bracket attached to the liquid ring pump.

FIG. 8 is a schematic illustration (not to scale) illustrating removalof a mechanical seal from a housing of the liquid ring pump.

FIG. 9 is a schematic illustration (not to scale) showing a supportmember coupled to the liquid ring pump.

FIG. 10 is a schematic illustration (not to scale) illustrating thefixing bracket and the mechanical seal being removed from the liquidring pump.

FIG. 11 is a schematic illustration (not to scale) illustrating areconditioned mechanical seal and the fixing bracket being attached tothe liquid ring pump.

FIG. 12 is a schematic illustration (not to scale) showing areconditioned bearing assembly being attached to the liquid ring pump.

DETAILED DESCRIPTION

FIG. 1 is a schematic illustration (not to scale) of an example singlestage liquid ring pump 2 that will be used to illustrate an embodimentof a maintenance and/or repair procedure.

The liquid ring pump 2 comprises a housing 4 that defines asubstantially cylindrical chamber 6, a shaft 8 extending into thechamber 6, and an impeller 10 fixedly mounted to the shaft 8. The liquidring pump 2 further comprises a gas inlet 12 fluidly connected to a gasintake of the chamber 6, and a gas outlet (not shown in the Figures)fluidly connected to a gas output of the chamber 6.

During operation of the liquid ring pump 2, the shaft 8 rotates therebyrotating the impeller 10 within the chamber 6. As the impeller 10rotates, an operating liquid (not shown in the Figures) is forcedagainst the walls of the chamber 6 thereby to form a liquid ring thatseals and isolates individual volumes between adjacent impeller vanes.Also, gas 14 (such as air) is drawn into the chamber 6 via the inlet 12and the gas intake of the chamber 6. This gas flows into the volumesformed between adjacent vanes of the impeller 10. The rotation of theimpeller 10 compresses the gas contained within the volume as it ismoved from the gas intake of the chamber 6 to the gas output of thechamber 6, where the compressed gas exits the chamber 6.

The housing 4 comprises a first end portion 16, a second end portion 18,and a central portion 20 disposed between the first and second endportions 16, 18. The first and second end portions 16, 18 are located atopposite axial ends of the central portion 20.

The chamber 6 is defined by interior walls of the central portion 20 ofthe housing 4. The longitudinal axis of the shaft 8 is offset, i.e.eccentric, relative to the axis of the central portion 20.

The first end portion 16 comprises a first mechanical seal 22 disposedbetween the shaft 8 and the walls of the chamber 6. The first mechanicalseal 22 forms a seal between the shaft 8 and the walls of the chamber 6thereby to prevent or oppose leakage of the gas and operating liquid outof the chamber 6 at the first end portion 16. The first mechanical seal22 is arranged to prevent or oppose radial movement of the shaft 8, i.e.in a direction that is substantially perpendicular to the longitudinalaxis of the shaft 8. The first mechanical seal 22 may prevent or opposeaxial movement of the shaft 8. The first mechanical seal 22 isconfigured to permit rotation of the shaft 8 about its longitudinalaxis.

The first end portion 16 further comprises a first bearing assembly 24disposed around the shaft 8 and axially outward of the first mechanicalseal 22. The first end portion 16 further comprises a first bearingcover 26 which houses the first bearing assembly 24 and covers a firstend of the shaft 8 at the first end portion 16. The first bearing cover26 is at the outboard end of the liquid ring pump 2.

The second end portion 18 comprises a second mechanical seal 28 disposedbetween the shaft 8 and the walls of the chamber 6. The secondmechanical seal 28 forms a seal between the shaft 8 and the walls of thechamber 6 thereby to prevent or oppose leakage of the gas and operatingliquid out of the chamber 6 at the second end portion 18. The secondmechanical seal 28 is arranged to prevent or oppose radial movement ofthe shaft 8, i.e. in a direction that is substantially perpendicular tothe longitudinal axis of the shaft 8. The second mechanical seal 28 mayprevent or oppose axial movement of the shaft 8. The second mechanicalseal 28 is configured to permit rotation of the shaft 8 about itslongitudinal axis.

The second end portion 18 further comprises a second bearing assembly 30disposed around the shaft 8 and axially outward of the second mechanicalseal 28. The second end portion 18 further comprises a second bearingcover 32 which houses the second bearing assembly 30 and covers a secondend of the shaft 8 (opposite to the first end of the shaft 8) at thesecond end portion 18.

The second end portion 18 further comprises a lantern ring 34 coupled tothe housing 4 and around the shaft 8, the second bearing assembly 30,and the second bearing cover 32. The lantern ring 34 is a perforatedhollow ring that, in operation, is used to couple the pump to the motor,supports the motor and the drive end casing, to the base frame.

FIG. 2 is a process flow chart showing certain steps of an embodiment ofmaintenance and/or repair procedure for a liquid ring pump. In thisembodiment, the maintenance and/or repair procedure is performed on theliquid ring pump 2 shown in FIG. 1 and described in more detail earlierabove.

In this embodiment, for the sake of brevity, the maintenance and/orrepair procedure is described as being performed on the first endportion 16 of the liquid ring pump 2 only. However, it will beappreciated by those skilled in the art that the below describedmaintenance and/or repair procedure may be performed at other areas ofthe liquid ring pump 2 instead of or in addition to being performed atthe first end portion 16. For example, in other embodiments themaintenance and/or repair procedure is performed on the second endportion 18 of the liquid ring pump 2 instead of or in addition to beingperformed at the first end portion 16. The maintenance and/or repairprocedure being performed at the second end portion 18 may be performedin series, in parallel, or partially overlapping temporally with themaintenance and/or repair procedure being performed at the first endportion 16. The maintenance and/or repair procedure performed at thesecond end portion 18 may be performed to inspect, clean, maintain, orreplace liquid ring pump one or more components located at the secondend portion 18 selected from the group of components comprising thesecond mechanical seal 28, the second bearing assembly 30, the secondbearing cover 32, the lantern ring 34, washers, seals, bearings, bolts,coupling mechanisms, V-rings, and circlips.

At step s2, a user (i.e. a human that is performing the maintenanceand/or repair procedure) removes the first bearing cover 26 from theliquid ring pump 2.

FIG. 3 is a schematic illustration (not to scale) showing the firstbearing cover 26 being removed from the liquid ring pump 2. In thisembodiment, the first bearing cover 26 is attached to the housing 4 atthe first end portion 16 by a first plurality of bolts 36. At step s2,the user removes from the liquid ring pump 2 the first plurality ofbolts 36, followed by the first bearing cover 26, as indicated in FIG. 3by solid arrows and the reference numeral 38.

At step s4, the user removes the first bearing assembly 24 from theliquid ring pump 2.

FIG. 4 is a schematic illustration (not to scale) showing the firstbearing assembly 24 being removed from the liquid ring pump 2. In thisembodiment, the first bearing assembly 24 fits around the shaft 8 andattaches to the housing 4 at the first end portion 16 by a secondplurality of bolts 40. A first washer 42 and a first spacer 44 arecoupled to an end of the shaft 8 between the first bearing assembly 24and the first bearing cover 26. At step s4, the user removes from theliquid ring pump 2, in turn, the second plurality of bolts 40, the firstwasher 42 and the first spacer 44, and the first bearing assembly 24, asindicated in FIG. 4 by solid arrows and the reference numeral 46.

At step s5, the user reconditions the first bearing assembly 24 ifrequired. For example, the user may inspect, clean, repair and/orreplace some or all of the components of the first bearing assembly 24that has been removed from the liquid ring pump 2. In some embodiments,the user replaces the first bearing assembly 24 with a new bearingassembly.

FIG. 5 is a schematic illustration (not to scale) showing an explodedview of the first bearing assembly 24. In this embodiment, the firstbearing assembly 24 comprises a second washer 50, a second spacer 52, abearing 54, a bearing spacer 56, a lip seal 58, and a bearing assemblyhousing 60. The user may disassemble some or all of the first bearingassembly 24 to perform maintenance, inspection, cleaning, repair orreplacement. The user may inspect, clean, repair, and/or replace one ormore of the component parts 50-60 of the first bearing assembly 24 priorto reassembling the first bearing assembly 24, thereby to provide areconditioned first bearing assembly 24.

At step s6, the user attaches a fixing bracket to the liquid ring pump 2(which has had the first bearing cover 26 and first bearing assembly 24removed).

FIG. 6 is a schematic illustration (not to scale) illustrating thefixing bracket 62 being attached to the liquid ring pump 2.

In this embodiment, the fixing bracket 62 is made of a metal.

In this embodiment, the fixing bracket 62 comprises a square U-shapedcentral portion having a base member 64 and two side members 66extending substantially perpendicularly from opposite ends of the basemember 64. The fixing bracket 62 further comprises two arms 68. Each arm68 is attached to a respective side member 66, at the opposite end ofthat side member 66 to the base member 64. The arms 68 extend outwardsfrom the side members 66 substantially parallel to the base member 64.

In this embodiment, the fixing bracket 62 comprises three holes, namelya first hole 71, a second hole 72, and a third hole 73. The first hole71 passes through the base member 64 substantially equidistant betweenthe ends of the base member 64. The second and third holes 72, 73 eachpass through a respective arm 68 of the fixing bracket 62.

The fixing bracket 62 is attached to liquid ring pump 2 via three bolts,namely a first bolt 81, a second bolt 82, and a third bolt 83.

The first bolt 81 passes through the first hole 71 in the base member64, and into a bore in the first end of the shaft 8, thereby fixedlyattaching the base member 64 to the shaft 8. The second bolt 82 passesthrough the second hole 72 of the fixing bracket 62 and into a bore inthe housing 4, thereby fixedly attaching an arm 68 of the fixing bracket62 to the housing 4. The third bolt 83 passes through the third hole 73of the fixing bracket 62 and into a bore in the housing 4, therebyfixedly attaching an arm 68 of the fixing bracket 62 to the housing 4.This attachment of the fixing bracket 62 to the shaft 8 and the housing4 via the first, second, and third bolts 81-83 is indicated in FIG. 6 bysolid arrows and the reference numeral 84. Preferably, the bores in thehousing 4 into which the second and third bolts 82, 83 are inserted arethe same bores as those used by two bolts from the first or secondpluralities of bolts 36, 40 (which were removed earlier in the processof FIG. 2).

FIG. 7 is a schematic illustration (not to scale) illustrating thefixing bracket 62 attached to the liquid ring pump 2. In thisembodiment, the fixing bracket 62 fixedly attaches the shaft 8 to thehousing 4 such that relative movement therebetween is prevented oropposed. Preferably, the fixing bracket 62 prevents the shaft 8 fromrotating about its axis, i.e. the fixing bracket 62 prevents rotation ofthe shaft 8 relative to the housing 4. Preferably, the fixing bracket 62prevents axial movement of the shaft 8 relative to the housing 4.Preferably, the fixing bracket 62 prevents radial movement of the shaft8 relative to the housing 4.

At step s8, the user removes (e.g. detaches or decouples) the firstmechanical seal 22 from the housing 4.

FIG. 8 is a schematic illustration (not to scale) illustrating removalof the first mechanical seal 22 from the housing 4. In this embodiment,the first mechanical seal 22 is detached from the housing 4 and slidalong the shaft 8 from the housing 4 towards the fixing bracket 62.Thus, the first mechanical seal 22 is moved such that it is spaced apartfrom the housing 4. This removal of the first mechanical seal 22 fromthe housing 4 is indicated in FIG. 8 by solid arrows and the referencenumeral 86.

At step s10, the user couples a support member between the shaft 8 andthe surface upon which the liquid ring pump 2 is installed (e.g. theground).

FIG. 9 is a schematic illustration (not to scale) showing the supportmember 90 coupled between the shaft 8 and the surface 92 upon which theliquid ring pump 2 is installed. In some embodiments, the liquid ringpump is attached (e.g. by bolts) to the surface 92.

In this embodiment, the support member 90 is an elongate metal member.

The support member 90 is coupled to the shaft 8 at a position along theshaft 8 between the first mechanical seal 22 and the housing 4. Thus,the support member 90 does not impede the later removal of the firstmechanical seal 22 from the first end of the shaft 8.

The support member 90 fixedly couples the shaft 8 to the surface 92 ontowhich the housing 4 is secured. Thus, the shaft 8 is securely coupled tothe housing via the support member 90. Preferably, the support member 90prevents the shaft 8 from rotating about its axis, i.e. the supportmember 90 prevents rotation of the shaft 8 relative to the housing 4.Preferably, the support member 90 prevents axial movement of the shaft 8relative to the housing 4. Preferably, the support member 90 preventsradial movement of the shaft 8 relative to the housing 4.

At step s12, the user removes the fixing bracket 62 from the liquid ringpump 2. In this embodiment, the fixing bracket 62 is detached from theend of the shaft 8 and from the housing 4.

At step s14, the user removes the first mechanical seal 22 from theshaft 8.

FIG. 10 is a schematic illustration (not to scale) illustrating thefixing bracket 62 and the first mechanical seal 22 being removed fromthe liquid ring pump 2 In this embodiment, at step s14 the user removesfrom the liquid ring pump 2 the first, second, and third bolts 81, 82,83, followed by the fixing bracket 62, followed by the first mechanicalseal 22, as indicated in FIG. 10 by solid arrows and the referencenumeral 94.

At step s15, the user reconditions the mechanical seal 22 if required.For example, the user may inspect, clean repair and/or replace some orall of the components of the first mechanical seal 22. In someembodiments, the user may replace the first mechanical seal 22 with anew mechanical seal.

At step s16, the user places the reconditioned mechanical seal onto thefirst end of the shaft 8 outward of the support member 90.

At step s18, the user attaches the fixing bracket 62 to the liquid ringpump 2 (which has the first bearing cover 26 and assembly 24 removed).

FIG. 11 is a schematic illustration (not to scale) illustrating thereconditioned first mechanical seal 22′ and the fixing bracket 62 beingattached to the liquid ring pump 2. In this embodiment, thereconditioned mechanical seal 22′ is first placed onto the first end ofthe shaft 8, and the fixing bracket 62 is subsequently attached to theshaft 8 and the housing 4 by the first, second, and third bolts 81, 82,83 in the same way as performed at step s6 (and described in more detailearlier above with reference to FIG. 6). The reconditioned firstmechanical seal 22′ is thus located between the fixing bracket 62 andthe support member 90. This attachment of the reconditioned firstmechanical seal 22′ and the fixing bracket 62 to the liquid ring pump 2is indicated in FIG. 11 by solid arrows and the reference numeral 96.

At step s20, the user removes the support member 90 from between theshaft 8 and the surface 92. Thus, the support member 90 is decoupledfrom the shaft 8. Relative positions of the shaft 8 and the housing 4are maintained by the fixing bracket 62.

At step s22, the user installs the reconditioned first mechanical seal22′ in the liquid ring pump 2. In this embodiment, the reconditionedfirst mechanical seal 22′ is slid along the shaft 8 into the housing 4.The reconditioned first mechanical seal 22′ is then coupled between thehousing 4 and shaft 8 in the same way as it was before it was removedand reconditioned at step s14 and s15 respectively.

At step s24, the user removes the fixing bracket 62 from the liquid ringpump 2. In this embodiment, the fixing bracket 62 is detached from theend of the shaft 8 and from the housing 4. Correct positioning betweenthe shaft and the housing 4 is provided by the reconditioned firstmechanical seal 22′.

At step s26, the user attaches the reconditioned first bearing assembly24 to the liquid ring pump 2.

FIG. 12 is a schematic illustration (not to scale) showing thereconditioned first bearing assembly 24′ being attached to the liquidring pump 2. In this embodiment, the reconditioned first bearingassembly 24′ fits around the shaft 8 and attaches to the housing 4 atthe first end portion 16 by the second plurality of bolts 40. Thus, thereconditioned first bearing assembly 24′ is coupled to the housing 4 andshaft 8 in the same way as it was before it was removed andreconditioned at steps s4 and s5 respectively.

In this embodiment, the first washer 42 and the first spacer 44 arecoupled to the first end of the shaft 8 in the same way as they werebefore they were removed at step s4. In some embodiments, the firstwasher 42 and/or the first spacer 44 are reconditioned (e.g. cleaned orrepaired) prior to reattachment to the liquid ring pump 2. In someembodiments, the first washer 42 and/or the first spacer 44 are replacedby new parts which are then attached to the liquid ring pump 2.

The attachment of the reconditioned first bearing assembly 24′, thefirst washer 42, and the first spacer 44 to the liquid ring pump 2 isindicated in FIG. 12 by solid arrows and the reference numeral 98.

At step s26, the user reattaches the first bearing cover 26 to theliquid ring pump 2.

In this embodiment, the first bearing cover 26 is reattached to thehousing 4 at the first end portion 16 by the first plurality of bolts36. Thus, the first bearing cover 26 is coupled to the housing 4 andshaft 8 in the same way as it was before it was removed at step s2.

In some embodiments, the first bearing cover 26 is reconditioned (e.g.cleaned or repaired) prior to reattachment to the liquid ring pump 2. Insome embodiments, the first bearing cover 26 is replaced by a new partwhich is then attached to the liquid ring pump 2

Thus, a maintenance and/or repair procedure for a liquid ring pump isprovided.

Advantageously, the above-described maintenance and/or repair proceduremay be performed while the shaft of the liquid ring pump issubstantially horizontal, e.g. substantially parallel to the surfaceupon which the liquid ring pump is installed. In other words,maintenance and/or repair of the liquid ring pump may be performed withthe liquid ring pump in its installed state. During the procedure, theshaft is secured in its substantially horizontal position such thatmovement of the shaft relative to the housing is prevented or opposed.This tends to reduce the likelihood of components of the liquid ringpump being damaged during the procedure. For example, undesirablebending of the shaft which may damage the shaft tends to be reduced oreliminated. Also, the likelihood of the impeller vanes mounted to theshaft impacting the walls of the housing, which may damage the vanesand/or housing, tends to be reduced or eliminated.

Furthermore, the above-described maintenance and/or repair proceduretends to avoid the conventionally implemented process of suspending theliquid ring pump above the ground, and rotating it through about 90° sothat the shaft is substantially vertical. Thus, a need for apparatus forlifting, rotating, and suspending the liquid ring pump tends to beavoided. Also, a risk that component parts disassembled or loosenedduring maintenance fall from the liquid ring pump and become damaged isreduced or eliminated. This further tends to improve the safety ofpersonnel carrying out maintenance or repair of the liquid ring pump.

The above-described maintenance and/or repair procedure tends to requirefewer personnel and less equipment compared to conventional techniques.

The above-described maintenance and/or repair procedure tends to providefor faster maintenance and/or repair of a liquid ring pump compared toconventional techniques.

It should be noted that certain of the process steps depicted in theflowchart of FIG. 2 and described above may be omitted or such processsteps may be performed in differing order to that presented above andshown in FIG. 2. Furthermore, although all the process steps have, forconvenience and ease of understanding, been depicted as discretetemporally-sequential steps, nevertheless some of the process steps mayin fact be performed simultaneously or at least overlapping to someextent temporally.

In the above embodiments, the maintenance and/or repair procedure isimplemented on a single stage liquid ring pump. However, in otherembodiments, the maintenance and/or repair procedure is implemented on adifferent type of liquid ring pump, e.g. a multi-stage liquid ring pump.In some embodiments, the maintenance and/or repair procedure isimplemented on a liquid ring pump that has different components to thosedescribed above, or components that may be arranged or connectedtogether in a different way.

In the above embodiments, the maintenance and/or repair procedure may beperformed to inspect, clean, maintain, repair or replace liquid ringpump components including but not limited to the first mechanical seal,the first bearing assembly, the first bearing cover, and/or washers andseals located at the first end portion. However, in other embodimentsinspection, cleaning, maintaining, or replacement of one or more otherliquid ring pump components is performed instead of or in addition tothose described above, for example, coupling mechanisms, housings,washers, spacers, seals, bearings, belts, belt drives, V-rings,circlips, bolts, and nuts.

In the above embodiments, the fixing bracket is made of metal. However,in other embodiments, the fixing bracket comprises a different materialinstead of or in addition to metal.

In the above embodiments, the fixing bracket comprises a square U-shapedcentral portion with two arms extending from the end of that squareU-shaped central portion. However, in other embodiments the fixingbracket has a different shape.

In the above embodiments, the fixing bracket attaches to the shaft andthe housing via three bolts which pass through respective holes in thefixing bracket. However, in other embodiments, the fixing bracket isfixedly attached to the shaft and/or the housing in a differentappropriate way, for example, via a different number of bolts. Thefixing bracket may have a different number of holes for receiving adifferent number of bolts.

In the above embodiments, at steps s6 and s18, the fixing bracket isattached between an end of the shaft and the housing, thereby to preventor oppose relative movement of the shaft and housing. However, in otherembodiments, at one or both of these steps, relative movement of theshaft and housing is prevented or opposed in a different way. Forexample, in some embodiments, at one or both of steps s6 and s18, asupport member (or other structure) is attached between the end of theshaft and the surface upon which the liquid ring pump is installed (e.g.the ground), thereby to prevent or oppose relative movement of the shaftand housing.

In the above embodiments, the support member is made of metal. However,in other embodiments, the support member comprises a different materialinstead of or in addition to metal.

In the above embodiments, the support member is an elongate member.However, in other embodiments the support member has a different shape.

In the above embodiments, at step s10, the support member is attachedbetween the shaft and the surface upon which the liquid ring pump isinstalled, thereby to prevent or oppose relative movement of the shaftand housing. The support member is coupled to the shaft at anintermediate position along the length of the shaft between the firstmechanical seal and the housing. However, in other embodiments, at steps10, relative movement of the shaft and housing is prevented or opposedin a different way. For example, in some embodiments, at steps s10, afixing member is attached directly between the shaft and the housing,thereby to prevent or oppose relative movement of the shaft and housing.The fixing member may attach to the shaft at the intermediate positionalong the length of the shaft between the first mechanical seal and thehousing.

In the above embodiments, many of the above described method steps areperformed by a human user using any appropriate tools. However, in otherembodiments. However, in other embodiments one or more of the abovedescribed method steps is performed by a different entity, for example acomputer-controlled robot arm.

In the above embodiments, the mechanical seal is removed from the liquidring pump at an end of the shaft. However, in other embodiments, themechanical seal is not removed from the liquid ring pump. For example,in some embodiments, a maintenance operation (e.g. cleaning or repair)may be performed on the mechanical seal while that mechanical sealremains disposed on the shaft. Thus, in some embodiments, steps s10-s14and s16-s20 may be omitted from the maintenance and/or repair procedure.

In some embodiments, while the mechanical seal is spaced apart from thehousing, a maintenance operation is performed on the housing of theliquid ring pump, or on a component on or within the housing that isaccessible by virtue of the mechanical seal being spaced apart from thehousing.

1. A method for decoupling a liquid ring pump component from a liquidring pump, the liquid ring pump comprising a housing defining an annularchamber and a shaft passing into the chamber, the component beingdisposed around the shaft and coupled between the shaft and the housing,the method comprising: coupling, using a first fixing member, a firstend of the shaft to the housing thereby to prevent or oppose movement ofthe shaft relative to the housing in at least a radial direction; andthereafter, sliding the component along the shaft in a direction alongthe shaft from the housing towards the first end of the shaft, therebyspacing apart the housing and the component.
 2. The method according toclaim 1, further comprising: while the component and the housing arespaced apart, inspecting, cleaning, repairing or replacing the componentor a further component of the liquid ring pump; and, thereafter, slidingthe component along the shaft in a direction along the shaft from thefirst end of the shaft towards the housing; and coupling the componentbetween the shaft and the housing.
 3. The method according to claim 1,wherein the first fixing member is a member selected from the group ofmembers consisting of: a fixing bracket configured to fixedly attachbetween the first end of the shaft and the housing, and a support memberconfigured to be coupled between the shaft and a surface upon which theliquid ring pump is located.
 4. The method according to claim 3,wherein: the first fixing member is a bracket comprising a base member,two side members extending substantially perpendicularly from oppositeends of the base member, and two arms, each arm being attached to arespective side member at the opposite end of that side member to thebase member, the arms extending outwards from the side memberssubstantially parallel to the base member; and coupling the first end ofthe shaft to the housing comprises bolting the fixing bracket to theshaft and the housing.
 5. The method according to claim 4, whereinbolting the fixing bracket to the shaft and the housing comprisesinserting a bolt into a hole in the housing, the hole being a hole viawhich a bearing assembly or bearing assembly cover is bolted to theliquid ring pump.
 6. The method according to claim 1, furthercomprising: coupling, using a second fixing member, the shaft to thehousing, the second fixing member configured to prevent or opposemovement of the shaft relative to the housing in at least a radialdirection, wherein the second fixing member is coupled to the shaft at aposition along the length of the shaft that is further away from thefirst end than the component; decoupling the first fixing member fromthe first end of the shaft; and removing the component from the shaft atthe first end of the shaft.
 7. The method according to claim 6, furthercomprising: inspecting, cleaning, repairing or replacing the removedcomponent, thereby to provide a reconditioned or replacement component;disposing the reconditioned or replacement component around the shaft atthe first end of the shaft; coupling, using a fixing member, a first endof the shaft to the housing, the fixing member configured to prevent oroppose movement of the shaft relative to the housing in at least aradial direction; decoupling the second fixing member from the shaft;sliding the reconditioned or replacement component along the shaft in adirection along the shaft from the first end of the shaft towards thehousing; coupling the reconditioned or replacement component between theshaft and the housing; and thereafter, decoupling the fixing member fromthe first end of the shaft.
 8. The method according to claim 6, whereinthe second fixing member is a member selected from the group of membersconsisting of: a fixing bracket configured to fixedly attach between theshaft and the housing, and a support member configured to be coupledbetween the shaft and a surface upon which the liquid ring pump islocated.
 9. The method according to claim 1, wherein the component is amechanical seal.
 10. The method according to claim 1, furthercomprising: prior to coupling the first end of the shaft to the housingusing the first fixing member, removing, from the liquid ring pump at orproximate to the first end of the shaft, one or more liquid ring pumpcomponents selected from the group of components consisting of: abearing cover, a bolt, a spacer, a washer, a bearing assembly, abearing, a seal, a lantern ring, a V-ring, and a circlip; andinspecting, cleaning, repairing or replacing the removed one or moreliquid ring pump components, thereby to provide a reconditioned orreplacement one or more liquid ring pump components.
 11. The methodaccording to claim 1, wherein coupling, using the first fixing member,the first end of the shaft to the housing further prevents or opposesaxial and/or rotational movement of the shaft relative to the housing.12. The method according to claim 1, wherein the shaft is retained in asubstantially horizonal orientation.
 13. The method according to claim1, further comprising: coupling, using a third fixing member, a secondend of the shaft to the housing thereby to prevent or oppose movement ofthe shaft relative to the housing in at least a radial direction, thesecond end of the shaft being opposite to the first end; and,thereafter, sliding a further component along the shaft in a directionalong the shaft from the housing towards the second end of the shaft,thereby spacing apart the housing and the component.
 14. The methodaccording to claim 13, wherein the steps of coupling the second end ofthe shaft to the housing and sliding the further component along theshaft towards the second end of the shaft overlap temporally at least tosome extent with the steps of coupling the first end of the shaft to thehousing and sliding the component along the shaft towards the first endof the shaft.
 15. A system comprising: a liquid ring pump comprising: ahousing defining an annular chamber; a shaft coupled to the housing andpassing through the housing into the chamber; and a component disposedaround the shaft and coupled between the shaft and the housing andconfigured to prevent or oppose movement of the shaft relative to thehousing in at least a radial direction; and a fixing member configuredto couple together a first end of the shaft and the housing thereby toprevent or oppose movement of the shaft relative to the housing in atleast the radial direction.